Latch-releasing device for dry pipe valves



March 22,1927. 1,621,872

H. G. CARLSON LATH RELEASING DEVICE FOR DRY PIPE VALVES Filed Feb. 4. 1926 2 Sheets-Sheet 1 fimws/" fijfahzar G, Car/J00 March H. G-ILARLSON LATH RELEASING DEVICE FOR DRY PIPE VALVES Filed Feb. 4. 1926 2 Sheets-Sheet 2 I W/ "Q Ha/mar G Car/$00 Patented Mar. 22, 1927.

UNITED STATES PATENT oFFlcE.

HJALMAR Gr. CARLSON, F VJOIEt-CESTER, MASSACHUSETTS, ASSIGNOR TO ROCKWOQD SPRINKLER COMPANY OF MASSACHUSETTS, OF WORCESTER, MASSACHUSETTS, A

CORPORATION OF MASSACHUSETTS.

LATCH-RELEASING DEVICE FOR DRY PIPE VALVES.

Application filed February 4, 1826. Serial No. 86,073.

This invention relates to that type of dry-pipe valve in which the valve is con-- nected to a counter-weighted lever so as to be held open, once it has been opened; and which is further provided with a latch for engaging said lever after partial or complete opening movement and preventing its swing-- ing the valve to its seat again. This type of dry-pipe valve is widely adopted, but is open to the objection that when the valve is fully raised and the gravity detent, or latch, usually employed, had swung in behind a toothv on the lever to prevent the closing of the valve, it has been necessary to reach a bar in through the hand hole in the body and around the valve in order to release the latch from the lever and permit the closing of the valve again. The workman might possibly leave such a bar or other tool in the casing after setting the valve and thus prevent its subsequent opening to admit water to extinguish a lire. Furthermore, the latch cannot engage the lever at an earlier pointin its return swing than will permit motion enough to allow the insertion of a bar over the top of the valve and under the latch to disengage it, after pulling down the valve far enough for the purpose.

The particular object of this invention is to provide safe means for releasing the latch from outside the valve casing and also not only to make the use of a bar unnecessary, but to permit the latch to hold the valve in its extreme open position, otherwise impossible since a bar could not, in that position, be applied to the latch.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the accompanying drawing, in whi.ch-

Fig. 1 is a central sectional view through a dry pipe valve casing of a well known type showing the application of this invention thereto;

Fig. 2 is an enlarged sectional view of a portion thereof; and

Fig. 3 is a horizontal section taken on the line 33 of Fig. 2.

The invention is shown as applied to a dry pipe valve casing having a valve 11 of usual construction, attached to a lever 12 which, in this case, is provided with a weight 13 of lead. This lever, as is usual, is

provided with one or more teeth 1% on its convex surface, on which the end of a gravity swing latch is adapted to rest. When the valve is opened and the lever is brought back to the full retracted position shown or to an intermediate position, the latch will drop down by gravity in front of one of the seve ral teeth 14 shown. Although the latch does not thereby prevent a slight rotary movement of the lever, it does prevent motion beyond the position in which the latch would engage the next tooth.

The uses of a valve, valve arm with teeth and latch in a dry pipe valve are all old and well known. As alluded to above, it has been customary heretofore tov release the latch 15 by inserting a bar or tool through a hand hole covered by a removable coverplate 16. This is an awkward job for the reason that the latch has to be held up out of contact with the teeth until the lever 12 is turned over to practically the closed position of the valve 11; that is, until the last tooth 14 is past the end of the latch.

Then the operator has to remove the tool.

bar or stick, whichever he may have used to trip the latch, before closing the cover and sealing the system air tight.

This invention involves the provision of an opening 19 through the wall or the valve casing adjacent to the end of the latch 15 and particularly to a projection 20 on the latch on the opposite side of the pivot from the main weight of the latch. In this opening is screwed a bushing 21, inside which is a plunger 22 located centrally. There is a passage 23 through which the plunger moves and at its lower end this is provided with a seat. The plunger is provided with an enlargement 24: and a soft metal or other packing 25 upon it, constituting a valve for closing the seat air tight when the plunger is fully withdrawn, as shown in the drawing. This plunger is provided with a screwthreaded end 26 on which there is a nut 27 provided with a hand wheel 28. The nut 27 is provided with a cap 29 so that the hand wheel and nut, although rotatable together, cannot be moved longitudinally. The screw isprovided with a collar 30 secured to it by av pin 31. On the collar is a radial arm 32 extending into a longitudinal slot 33 in the wall of the bushing 21. This allows the screw to move longitudinally but keeps it from turning V In operation, assuming that the dry pipe valve is opening and the lever weight moving down until one of the teeth 14 passes the end of the latch15, the latter will drop down behind it and positively prevent the closing of the valve. After the fire is out and it is desired to pump air into the .systern again, the operator first opens the hand hole cover, then turns the hand wheel 28 and screws the plunger down as far as it will go. Its end engages the projection 20, thereby swinging thelatch 15 up out of the path of the teeth. Now the' valve can be pulled down to its seat by hand, the latch being left up until the valve is closed.- The cover is then bolted to its seat. An under pressl e cannot be retained in the system as yet b'ecaiise', the plunger being down, there will be a leakage through the opening 23. Therefore the plunger 22 has to be screwed upwards to its seat, which operation raises its lower end clear up out of the way of the projection so that it cannot then affect the operation of the latch as a detent.

The device therefore thus constitutes a very simple, certain and inexpensive means for operating the latch from the outside of the valve body, without the danger of leaving it in contact with the latch when the system is set under air pressure,

Although I have illustrated and described only a single form of the invention I am aware of the fact that modifications can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims. Therefore I do not wish to be'limited to the details herein disclosed but what- I do claim is:

1; In a dry'p'ipe valve, the combination withthe valve, a lever connected with it and having ratchet teeth on its surface, and a pivoted gravity latch, the long arm of which engages said teeth to prevent the accidental closing otthe valve, of means extending through the valve casing for engaging the short end of the latch and swinging it into a position in which the long end of the latch is out of contact with the lever.

2. In a dry pipe valve, the combination with the valve, and a latch for preventing the accidental closing of the valve, of a plunger extending through the wall of the Valve casing for moving the latch into inoperative position, a bushing screwing into the wall of the valve casing, a nut carried by said bushing, the plunger having threads for engaging the nut, and means for preventing the rotation of the plunger, whereby the rotation of the nut will move the plunger in or out.

3. In a dry pipe valve, the combination with the valve, a lever mova le with it as the valve opens and having ratchet teeth on its surface, and a pivoted gravity latch for engaging in front of said teeth and preventing the closing of the valve, said latch having a short end extending beyond the pivot, of a bushing in the wall of the casing, a plunger located in the bushing in position to engage said short end and release the latch, the bushing having a passage for the plunger larger than the shank of the plunger and a valve seat surrounding the plunger, and a valve on the plunger adapted to close said seat only when the plunger is moved outwardly to its extreme position.

4. In a dry pipe valve, the combination with the valve, and a gravity latch for preventing the accidental closing of the valve, of a plunger extending through the wall of the valve casing for engaging the latch and moving it into inoperative position, a bushing screwing into the wall of the valve casing, a nut carried by said bushing, a hand wheel fixed to the nut, the bushing having a longitudinal slot, an arm projecting from the plunger into said slot to prevent the plunger from turning, and screw threads on the plunger for engaging the nut, whereby the rotation of the nut will move the plunger in or out.

In testimony whereof I have hereunto atfixed my signature.

HJALMAR G. CARLSON. 

